Background Ankle sprains are typically sustained during change of direction tasks and often occur during the latter thirds of both halves of matches. The effects of fatigue on turning kinematic characteristics have not been studied in a chronic ankle instability population.
Objective To analyse the effects of fatigue on lower limb movement during a change of direction task in those with chronic ankle instability.
Design Case-controlled study.
Setting Sports hall.
Patients (or participants) Twelve athletes with CAI and 11 athletes with no previous ankle sprain history were recruited for this study. Inclusion criteria for the CAI group were based on previously published recommendations. All athletes were currently playing sport and free of injury. Only data from athletes who turned consistently on the same foot in controls and on the same unstable ankle in the CAI group were included in analysis (4 CAI, 5 controls).
Interventions (or assessment of risk factors) Utilisation of 6 Shimmer 3D inertial sensors attached to each thigh, shank, and foot was used to collect the rate of change of the foot. The Yo-Yo Intermittent Recovery Test level 1 (Yo-Yo IR1) was used as the fatiguing protocol to allow for comparison of turning characteristics prior to and up to the point of maximal exhaustion.
Main outcome measurements Angular rate of rotation of the foot in the sagittal plane was analysed 400 ms before and after initial contact during the turn of each level of the Yo-Yo IR1 test.
Results Preliminary analysis has found an apparent trend in change of sagittal plane movement in the CAI group throughout the completion of the Yo-Yo IR1 test which may signify a change in control of movement with the onset of fatigue.
Conclusions Additional analysis is required before implementation into clinical settings. The identification of improper movements influenced by fatigue during a turning task in a CAI population may provide better insight on developing a more robust rehabilitation programme following an ankle sprain and may provide insight for developing a more effective injury prevention protocol.